1. Field of the invention
The present invention relates to a timer and, more particularly, to a mode selection arrangement for use in an electronic timer for selecting various counting modes, such as hour-counting mode, minute-counting mode, and second-counting mode, together with a scale change representing hour, minute or second, and various operation modes, such as on-delay mode, off-delay mode and program mode.
2. Description of the Prior Art
An electronic timer, which has been proposed lately, can operate under different modes by the change of internal circuit connection effected through a manual operation. According to one prior art, such a manual operation is done by a switch and, at the same time, a scale is replaced by another scale presenting the selected range. According to another prior art, such a manual operation is done by an insertion of a key which actuates the switch to change the range and carries an indication representing the selected range. The later is disclosed, for example, in British Patent Application Laid-Open Publication No. GB 2,085,202A (or a counterpart U.S. patent application Ser. No. 299,582 filed Sept. 4, 1981) assigned to the same assignee as this application.
In any of the prior art timers mentioned above, it is necessary to prepare more than one scale or one key, resulting in likelihood of losing parts, thus resulting in difficulty in maintenance. Furthermore, it is necessary to provide a number of switches corresponding to the number of different modes provided, resulting in high manufacturing cost and bulky in size, particularly the front operating panel portion.
Also, according to the prior art electronic timer, a sliding contact member defined by a comb shaped contact mounted on a rotator is provided such that the sliding contact member slides on a predetermined pattern of printed circuit.
This arrangement, however, has a poor contacting pressure between the contact member and the pattern, because the comb shaped contact is provided at the free end of the sliding contact member. If the contacting pressure is made stronger, it is likely that the sliding contact member rotates relatively to the rotator, when the rotator is rotated. This deteriorates the accuracy of positioning the sliding contact member.